A U.S. official said Thursday that while some Americans escaped from the complex, other Americans remained either held or unaccounted for. / Statoil via AFP/Getty Images

by Doug Stanglin and Michael Winter, USA TODAY

by Doug Stanglin and Michael Winter, USA TODAY

One day after al-Qaeda-linked militants took scores of foreigners hostage at a remote natural gas facility in Algeria, Algerian forces mounted a military operation Thursday against the Islamists, killing an unknown number of hostages and kidnappers, according to media reports.

The Algerian army had surrounded the In Amenas facility, which was taken over by militants in what they said was a response to Algeria aiding French troops fighting rebels in neighboring Mali.

As many as 20 foreign hostages, including an unknown number of Americans, were reported to have escaped during the attack by Algerian forces.

New reports indicated that dozens of hostages may have died in Thursday's operation, but reports are conflicting.

"They were moving five Jeep-loads of hostages from one part of the compound. At that stage, they were intercepted by the Algerian army," Brian McFaul said. "The army bombed four out of five of the trucks and four of them were destroyed.

"The truck my brother was in crashed, and Stephen was able to make a break for his freedom. He presumed everyone else in the other trucks was killed."

The hostages had explosives hung around their necks and their mouths taped, he said.

6:57 p.m. ET: The French news agency AFP and the British TV network ITN report that Algerian troops control only part of the site and that some terrorists escaped.

5:15 p.m. ET: Reuters, citing an Algerian security source, is reporting that 30 hostages were killed, including seven foreigners. Among them were two Britons, two Japanese and one French national.

The source also says 11 militants died, including the group's leader, Tahar Ben Cheneb, described as a "prominent commander in the region."

An Algerian worker who escaped told Reuters that the militants apparently had inside knowledge of the layout of the complex, and that they said they were targeting only non-Muslims.

"The terrorists told us at the very start that they would not hurt Muslims but were only interested in the Christians and infidels," Abdelkader, 53, said in a telephone interview from his home in nearby In Amenas. " 'We will kill them,' they said."

4:14 p.m. ET: The State Department says Secretary of State Hillary Rodham Clinton has ordered a review of security for U.S. diplomats, citizens and businesses across North Africa and the Maghreb region, which encompasses Algeria, Libya, Mauritania, Morocco and Tunisia.

3:54 p.m. ET: An unconfirmed report by an African news outlet cites militants as saying seven hostages survived, including two Americans, one Briton, three Belgians and a Japanese.

Algerian state TV reports at least four foreigners and 13 others were wounded.

Algerian Communications Minister Mohamed Said confirmed that there had been "several deaths and injuries" among the hostages.

"An important number of hostages were freed and an important number of terrorists were neutralized," Said told state media, the Russian news channel RT says.

3:07 p.m. ET: Japan's Vice-Minister of Foreign Affairs, Minoru Kiuchi, had flown to Algiers as the crisis grew, AFP reports, according to Le Monde. His office says he "urged the Algerian government to immediately stop its (military) operation."

2:59 p.m. ET: The official Algerian Press Service reports that the military operation at the gas field has concluded, The Guardian reports. The number of those wounded or killed was unavailable, the report said.

1:42 p.m. ET: Algerian Communications Minister Mohamed Said Belaid tells Algerian TV that the military operation at the gas facility in Algeria "is still going on," the BBC reports.

Belaid said that all measurees were taken to rescue the captives. "Unfortunately we deplore some deaths and some people wounded," he says. "We don't yet have the numbers."

1:35 p.m. ET: French President Francois Hollande told a group of business leaders in Paris that the hostage crisis in Algeria underscored that France had made the right decision in taking on Islamic militants in Mali, The Guardian reports. "What's happening in Algeria justifies even more the decision I took in the name of France to go to Mali's aid," he said.

1:20 p.m. ET: British Prime Minister David Cameron was not informed in advance of the Algerian military operation and learned of it only after phoning his counterpart in Algeria, the BBC reports. A British citizen and an Algerian were killed at the outset of the attack, the BBC says. A Downing Street spokesman said Cameron "is extremely concerned. It is a very grave and serious situation."

12:37 p.m. ET: White House spokesman Jay Carney, speaking at the noon briefing, says the United States is "seeking clarity" from Algeria over the hostage crisis.

Carney's remarks

"It is our understanding that there are Americans involved, but I would say a couple of things. One, we condemn in the strongest terms a terrorist attack on BP personnel and facilities in Algeria and we are closely monitoring the situation. We are in contact with Algerian authorities and our international partners as well as (the) BP security office in London."

"Unfortunately, the best information that we have at this time, as I said, indicates that U.S. citizens are among the hostages. But we do not have, at this point, more details to provide to you. We are certainly concerned about reports of loss of life and we are seeking clarity from the government of Algeria."

12:32 p.m. ET: Foreign nationals from eight countries were taken hostage. The Associated Press rounds up what we know about the hostages so far:

â?¢ Norway: Nine Norwegian employees of Statoil are hostages, the company says.

â?¢ United States: Seven Americans were hostages, the militants said, but they claimed only two survived the Algerian strafing on Thursday. The US has confirmed that some of its citizens are hostages but gave no numbers.

â?¢ Britain: "Several" British nationals are among the hostages, the UK government says.

â?¢ Japan: At least three of the hostages are Japanese, according to the Japanese media.

â?¢ Malaysia: Two Malaysians are being held, the government says.

â?¢ Ireland: A 36-year-old Irish man was among the hostages but is now safe and free, according to Ireland's government.

â?¢ France: President FranÃ§ois Hollande says there are French hostages but has given no exact number.

Hundreds of Algerians worked at the gas plant, but the Algerian media says most have been released. The Norwegian energy company Statoil says three of its Algerian employees are hostages.

11:49 a.m. ET: "The situation in Algeria is very fluid," says Peter Velasco, a spokesman for the U.S. State Department.

11:46 a.m. ET: Information continues to be difficult to pin down, but the Algerian news service, ANP, reports that almost 600 hostages were freed in the operation by Algerian forces.

11:39 a.m. ET: Ireland's Department of Foreign Affairs identified the freed Irish hostage as Stephen McFaul, 36, from Andersonstown in Belfast, The Irish Times reports. The newspaper says McFaul had managed to speak with his relative twice while still in captivity.

11:34 a.m. ET: An Irishman who wasa taken hostage has been freed and has spoken to his family, Ireland's foreign ministry said, the BBC reports.

11:03 a.m. ET: CNN's Barbara Starr reports that the U.S. is flying an unarmed drone over the gas facility to provide surveillance information on the site.

10:59 a.m. ET: Two hostages, identified as British and Irish, spoke to Al Jazeera TV and called on the Algerian army to withdraw from the area to avoid casualties, Reuters reports."We are receiving care and good treatment from the kidnappers. The (Algerian) army did not withdraw and they are firing at the camp,'' the British man tells Al Jazeera, according to Reuters. "There are around 150 Algerian hostages. We say to everybody that negotiations is a sign of strength and will spare many any loss of life.''

10:20 a.m. ET: A French national who says he is among the hostages tells France 24 that the captives are being forced to wear explosive belts and that the militants are "heavily armed."

He said the militants stormed the gas plant and the workers' living quarters. "They came in and once there was daylight, grouped us all together," he tells France 24..

10 a.m. ET: French President Francois Hollande, speaking at a news conference with the prime minister of Portugal in Paris, confirms that French nationals were among the hostages, but declines to provide details, saying, ""The situation is very confused and is changing from hour to hour." He said it was "best to say as little as possible," Le Figaro online reports.

9:55 a.m. ET: BP, which partially owns the gas facility, confirmed that an operation had taken place and that there are reports of casualties, but says the situation remains unclear, including that some hostages were freed or escaped. "Supporting these families is our priority and we are doing all we can to help during this sad and uncertain time," said Bob Dudley, BP Group Chief Executive.

BP says it has removed all "non-essential" employes from the site.

9:45 a.m. ET: The Algerian news agency APS reports that four foreign hostages were freed by the Algerian army during the military operation.

9:40 a.m. ET: The Associated Press quotes a militant spokesman as saying that 7 hostages remain alive, including from the U.S., Britain, Belgium and Japan..

9:32 am. ET: The Mauritanian ANI news agnecy, citing Islamist kidnappers, says the captors continue to hold two Americans, three Belgians, a Japanese and a British citizen, the French magazine Le Pointsays.

9:30 a.m. ET: ANI reports that the leader of the hostage-takers, Abu Al Baraa, was killed during the operation.

9:27 a.m. ET: Mauritania's ANI news agency, quoting the Masked Bridge militants, reports that 34 of the hostages and 15 of the militants had been killed when Algerian forces fired from helicopters as hostages were being transported to another location.

9:28 a.m. ET: Reuters, quoting a local source, reports that six foreign hostages and eight militants have been killed in the military assault on the gas facility in a remote area of Algeria. Reuters also reports that 180 hostages escaped.

9:23 a.m. ET: Reuters, quoting an unidentified sources, said the militants had demanded safe passage out with their prisoners but Algeria had refused to negotiate with them.